{3,3′-Bis[(anthracen-9-yl)meth­yl]-1,1′-[(ethane-1,2-diyldi­oxy)bis­(ethane-1,2-di­yl)]bis­(imidazol-2-yl­idene)}mercury(II) bis­(hexa­fluoridophosphate) acetonitrile disolvate

In the title compound, [Hg(C42H38N4O2)](PF6)2·2CH3CN, the HgII cation lies on a twofold axis which is also the inter­nal symmetry element of the complete cationic complex. The HgII cation is coordinated by two symmetry-related C(carbene) atoms [Hg—C = 2.058 (9) Å] in a nearly linear geometry, with a C—Hg—C angle of 175.8 (5)°. There are weak inter­molecular C—H⋯F inter­actions in the crystal packing between an F atom of a hexa­fluoridophosphate anion and a –CH2– group of the bis-N-heterocyclic carbene ligand

9,10-Bis{2-[1-(2-pyridylmeth­yl)imidazolium-3-yl]eth­oxy}anthracene bis(hexa­fluoridophosphate)

The cation of the title compound, C36H34N6O2 2+·2PF6 −, lies across a crystallographic inversion centre. The imidazole and pyridine rings form dihedral angles of 82.28 (5)° and 11.87 (7)°, respectively, with the anthracene ring system. The crystal packing is stabilized by π–π inter­actions between the pyridine ring and the central ring of anthracene, with a ring centroid–centroid distance of 3.684 (3) Å. The PF6 − anion is disordered over three different positions with occupancies of 0.284 (6), 0.354 (8) and 0.362 (9)

A scheme for dense coding in the non-symmetric quantum channel

We investigate the dense coding in the case of non-symmetric Hilbert spaces of the sender and receiver's particles sharing the quantum maximally entangled state. The efficiency of classical information gain is also considered. We conclude that when a more level particle is with the sender, she can get a non-symmetric quantum channel from a symmetric one by entanglement transfer. Thus the efficiency of information transmission is improved

Tunable Coupling Architectures with Capacitively Connecting Pads for Large-Scale Superconducting Multi-Qubit Processors

We have proposed and experimentally verified a tunable inter-qubit coupling scheme for large-scale integration of superconducting qubits. The key feature of the scheme is the insertion of connecting pads between qubit and tunable coupling element. In such a way, the distance between two qubits can be increased considerably to a few millimeters, leaving enough space for arranging control lines, readout resonators and other necessary structures. The increased inter-qubit distance provides more wiring space for flip-chip process and reduces crosstalk between qubits and from control lines to qubits. We use the term Tunable Coupler with Capacitively Connecting Pad (TCCP) to name the tunable coupling part that consists of a transmon coupler and capacitively connecting pads. With the different placement of connecting pads, different TCCP architectures can be realized. We have designed and fabricated a few multi-qubit devices in which TCCP is used for coupling. The measured results show that the performance of the qubits coupled by the TCCP, such as $T_1$ and $T_2$, was similar to that of the traditional transmon qubits without TCCP. Meanwhile, our TCCP also exhibited a wide tunable range of the effective coupling strength and a low residual ZZ interaction between the qubits by properly tuning the parameters on the design. Finally, we successfully implemented an adiabatic CZ gate with TCCP. Furthermore, by introducing TCCP, we also discuss the realization of the flip-chip process and tunable coupling qubits between different chips.Comment: Main text: 7 pages, 6 figure